Chasers War on Everything -- Americans (warning, viewing of this video may permanently alter or destroy any positive connotation you have previously associated with the phrase "proud to be an American"--apparently, math isn't the only thing we suck at.):http://www.youtube.com/watch?v=HCkYfYa8ePI

Just the other way around. People like to remix Shpongle's stuff. Shpongle's the psytrance producer. They got relatively popular a few years ago when Danny Gomez mashedup their song DMT (Divine Moments of Truth) with flash-animated video of a guy undergoing psychiatric hypnosis in a piece called Flashback.

you should enter the string theory contest, I for one would be very interested.

otherwise, pretty funny. I really liked the kuhn article: incommensurability is a pretty radical notion, and is probably not the best way to think about things. Other than than that, Kuhn was right, but ultimately what he is doing is the sociology of science, not the philosophy of science (without the incommensurability thesis).

My favorite thing about Weinberg's essay is the way he divides physical theories into "soft" and "hard" parts. I think this is exactly the right way to say it. If you're just looking at the soft parts, then sure... Kuhn was right. And the issue here seems to be that philosophers are more interested in the soft parts and scientists are more interested in the hard parts. From the science end, the soft part hardly even counts as a part of the theory at all... changing it is just a minor modification, whereas from the point of view of the philosopher, it's a complete overhaul that scraps the old theory entirely. When I see news articles on physics, they mostly talk about the soft parts... the qualitative aspects of a new theory. Unfortunately, that's not what scientists see as central to the theory, and it's not the part that's permanent.

I think there's a strong sense in which there is a set of hard facts about reality that science is slowly building up. They form the backbone of the theory... and by that I mean THE theory, the same single theory that's been building up from the beginning, where every revolution builds on the previous one. Some of the extraneous parts of the old theory get updated in favor of new stuff, but the core of it never gets scrapped (once a scientific consensus is acheived--obviously there are theories here and there that get suggested that just turn out wrong sometimes).

The hard parts of a theory are a one-way thing. Once they are learned, they never get unlearned. They just keep accumulating. The soft parts of the theory do get overturned, but this is why scientists tend to be ever more careful to include only the minimum amount of soft assumptions in a theory... since we know that they might need to be questioned or overturned some day.

It's always bothered me how much weight people outside of science place on the soft parts of physical theories and how little they care about or understand the hard parts... often not being able to distinguish between the two. Take for instance what's called the Big Bang theory. The hard part of the theory is that space has been undergoing uniform expansion and that 14 billion years ago the energy density in the universe was so high that the theory of general relativity itself breaks down. The point where general relativity breaks down is usually referred to as the "singularity". However, the parts of the theory that the media pays the most attention are entirely soft... namely, the idea that time actually began at the singularity, that somehow space and time were infinite, and that nothing whatsoever came before this moment. None of these parts need be true, they are just soft assumptions that get put there tenatively until we find out the rest of the story. The hard parts of the Big Bang model are facts, and will never be undone. Any theory which succeeds it (like eternal inflation, or the cyclic universe) still has to be compatible with the hard Big Bang theory, which has already been established as true. The soft assumptions got chosen since they're the simplest, and at the time of making them we didn't have any evidence yet that things were more complicated. But it's usually the case (and much moreso today than in the past) that physicists have a very good idea about which assumptions are soft and open to modification in the future. Each new theory builds on the previous theory, and must accept all of its hard tenets.

Ya, I shouldn't have said incommensurability was the only thing Kuhn got wrong. I think his picture of "normal science, crisis, revolution, normal science" is probably too tidy and, while a good metaphor for big shifts of thought for scientists, its not necessarily the most accurate description.

The soft parts/hard parts distinction was pretty interesting. And I think its actually appropriate for philosophers to concentrate on the soft parts and physicists to concentrate on the hard parts. The hard parts, as formula, models or what have you, are what are amenable to verification and falsification during periods of normal science. That sounds like work for scientists. The soft parts, however, are necessary for a coherent formulation of the theory, even if they aren't what the scientists find necessary. Maxwell couldn't have just published his equations and announced he was done: he had to postulate the ether in order for the formula to make sense. The equations could be preserved even with a rejection of this soft postulation, of course, but until the soft parts are rejected, they are still critically a part of the theory, even if physicists find that part uninteresting (or less interesting).

Thats why I think it is understandable to place some weight on the soft parts of physical theories. Physics is often taken, even by physicists, to be the story of how the world works, rather than just a set of equations or models that appear to match up with and predict observable phenomena. Physics as the story of the world would be incoherent without the soft parts of the theory. The soft parts of the big bang theory need not be true, as you say, but something needs to be true beyond just "GR does not describe what was happening 14 billion years ago" if physics is really THE story. It is this requirement for a complete picture that probably leads physicists to make their soft assumptions, but insofar as those assumptions are a part of the best theory we have of the world, it is worth considering what those assumptions would entail.

I mean, even you certainly think about the soft side of theories. After all, what else would the different QM interpretations be other than exactly different "soft" parts?

From a different perspective, I think the soft/hard parts really reflect a theory/fact distinction. The hard parts of the theory represent something like facts. As such, they aren't really theoretic at all, but are definitely part of our science, or paradigm, or whatever (and we can import them from previous paradigms, against Kuhn's incommensurability thesis). The soft parts of the theory, then, represent our attempts to explain these facts, and give coherent and consistent assumptions that are sufficient for those hard facts to obtain.

If this picture is a good one, then the hard parts do keep accumulating, and this does represent progress for science: an ever-increasing number of facts and regularities. However, our theories aren't like this: newtonian explanations and assumptions, for instance, aren't found in modern physics, even if newtonian equations can be. Insofar as every theory will require assumptions that help us translate our equations into observation statements, the soft parts are always going to be with us as an essential part of every theory. If they are there, they should be discussed (although with the caveat that they are open to revision in a way that the hard parts aren't firmly in mind).

insofar as those assumptions are a part of the best theory we have of the world, it is worth considering what those assumptions would entail.

I think we're very much in agreement here. Both soft and hard parts are worth thinking about, and it makes sense for philosophers to focus on the soft parts and scientists to focus on the hard parts. And the line is not always perfectly clear, so both groups end up having to think somewhat about both.

And it's true that I'm interested in both. (Example: interpretting quantum mechanics.) Some of the soft parts are purely philosophical, and I wouldn't expect to be able to publish in a scientific journal on them, but I'm still interested in those questions from a personal standpoint. (I've also considered publishing to a philosophy journal on them, but I think I would need help from people in the field in order to know that I've cited all the right people and not said anything embarassingly stupid.) Other soft parts I think are important to understand in order for physicists to make more progress, and also for them to be able to explain the theory in a coherent way to people.

However, our theories aren't like this: newtonian explanations and assumptions, for instance, aren't found in modern physics, even if newtonian equations can be.

I think I would disagree here, depending on what you mean by "in modern physics". If I'm going to describe how a car moves on the freeway, regardless of how much modern physics I know, I'm still going to give Newtonian explanations. Even fully believing in the framework of modern physics, Newtonian physics is still the most appropriate language to talk in for many situations. Newtonian physics deals with emergent phenomena that on a fundamental level are only approximate and in some sense not "real" physical entities, but they are nevertheless useful concepts.

Regarding the distinction between theory and fact, that's a good point to bring up. I thought of that after I wrote my last comment to you, and wondered whether I should have addressed something about it. I think this is a seperate distinction, although they do seem very similar. I've got to run right now, but there is more I'd like to write about this if I get a chance.

I've also considered publishing to a philosophy journal on them, but I think I would need help from people in the field in order to know that I've cited all the right people and not said anything embarassingly stupid.

heh, one day I hope to be qualified to offer such comments. In any case, I think it can only be a good thing for physicists and philosophers to talk to each other more, and cross-publishing might be a good way of doing this (although I'd be more wary about philosophers publishing in physics journals).

I think I would disagree here, depending on what you mean by "in modern physics". If I'm going to describe how a car moves on the freeway, regardless of how much modern physics I know, I'm still going to give Newtonian explanations...Newtonian physics ... nevertheless useful concepts."

Right, I guess I just don't buy that "just because we teach and talk like newtonians means we really accept newtonian explanations." Because those explanations refer to concepts/entities that are not found in a formal, rigorous description of modern physics I don't think that those explanations should be found in a formal, rigorous description either. Newtonian equations, however, could easily be found given an appropriately idealized scenario, I think. In other words, the hard part stays while the soft part goes (as I think was partly your point).

As for the theory/fact distinction: it might not be quite the same thing as the soft/hard distinction (and both are probably pretty fuzzy distinctions when you get right down to it. if you go all the way down to quine both distinctions would actually not be real distinctions at all), although I think they are at least pretty similar, as you say. In any case, hopefully you do end up writing a comment distinguishing the two :).

As for the theory/fact distinction: it might not be quite the same thing as the soft/hard distinction (and both are probably pretty fuzzy distinctions when you get right down to it. if you go all the way down to quine both distinctions would actually not be real distinctions at all), although I think they are at least pretty similar, as you say.

Indeed, they are both fuzzy distinctions, and that's part of it. Now, let's see if I can remember what I was going to say here...

The main thing I wanted to argue here is that there is a such thing as a "hard" part of theories... it's not just that theories are soft and facts are hard. I think the hard part of a theory is mostly the mathematics behind it. Regardless of what answer you give to the question of "why" planets move on the paths they do, it's already been established that they move along particular paths, and the theory predicts what those paths will be. When we went from classical to quantum physics, we didn't throw away that part of the theory, because it was already established. You might imagine a (crazy) possible world where one year someone comes up with an equation that successfully describes elliptical orbits, and all the scientists accept it, and then later they have a revolution where they decide instead they follow square orbits, not elliptical. Well, that kind of thing just never happens in the actual world. Once we've determined that they do follow paths described by certain equations, the only possible modification to that in the future is to modify the equations slightly, adding minor corrections (for instance, amending circular orbits to be elliptical. or adding a perihelion shift). Having a set of equations that tell you what's going to happen if you do a certain experiment is more than just having a collection of facts... it actually gives you an infinite number of experiments you could do. So it's definitely more on the "theory" side than the fact side. However, it's hard rather than soft. Does that make sense?

It is much less difficult for scientists in one period of normal science to understand the theories of an earlier paradigm in their mature form.

Actually the fallacy of both Kuhn and Weinberg is not accounting for the idea that periodizing history is an arbitrary, artificial thing to do and the paradigm shifts are more gradual then sudden flip-flops. On that note, there are shades of grey between any two points between theories, the more extreme the points the more incommensurable the two theories. (Which is practically recapitulating what Weinberg said, but I say it in this manner because I feel all Weinberg is doing is recapitulating Kuhn in his own understanding rather then really contradicting him.)

Also, without denying that there IS an objective reality out there or truth, science is NOT the progression towards the objective reality or truth but a set of models seeking to translate that reality into a universal language compatible with our senses. Science works because we have a common set of senses to view a single objective reality, so it's almost as good as saying that we're studying reality itself, but we will always be limited subjectively by our senses as to what reality really is. We were not made to be aware of more then three spatial dimensions for example, so any theory of science that requires more to explain the universe is really just a model of these higher dimensions, not what these dimensions might actually look or act like. It may in fact be possible (though I certainly do not hope so) that our experience of the small (modeled by quantum mechanics) and our experience of the large (modeled by relativity) are truly flat out contradictory not due to the nature of reality but due to the nature of our consciousness, and therefore may never be able to be resolved by the methods of science. Given this, Kuhn's views on scientific progress make complete sense and ring true to me.

Good points. I agree that even the biggest examples of paradigm shifts are continuous to some extent... it's usually not something that happens overnight, it happens gradually. But I am willing to give Kuhn the benefit of the doubt on this point... if you look at the history, at least in the case of physics which is the only branch of science I know well, there are certain insights that happened that could accurately be described as a paradigm shift. And I don't think those places are entirely arbitrary.

The only thing you say that I don't really agree with is regarding quantum mechanics and general relativity. While in the abstract I could imagine myself as some sort of floating being that wasn't really generated by a physical world in the first place, and some sort of Cartesian demon tricking me by giving my contradictory experiences (one set pulled from one consistent reality, and another set pulled from a second reality which is incompatible with the first) I don't consider this a serious possibility. If there is any external reality whatsoever, then not all of the assumptions of GR and QM can be true at once. One of them must be only approximately correct.